KM-5050 CQ issue on trail edge

**nathansipe** · 06-01-2016

Reposted without "print" at the end of the title. My apologies. I had no idea it would do that.
Thanks for letting know Blackcat!

We've been working on a low volume KM-5050 with only 293,000 prints on it and could use some advice. A couple weeks ago, it started making some type of line and skew across the trail edge of all prints. There's 2 photos of the issue, one LT and one LTR. The problem is always in the exact same spot and it never repeats across the paper like a roller would. It also never jams. About 2 inches from the trail edge of each print, it leaves a thin darkened line and slightly skews the last 2 inches of the print. Even on blank prints, it leaves a gray line across the paper in that same spot.

It is not an optic issue as the internal prints have the same issue.

The drum unit, main charge, and fuser were replaced at 112,000 prints a few years ago. I've cleaned/checked over the units and they all look great and DV unit turns smoothly. The resist roller in the door looks like it turns normally. It prints the same from each tray also. It seems like a timing issue of some sort to me so I cleaned and checked the feed, resist clutches. Nothing I've done has made any difference at all.

Since, the issue is on the trail end, could it be that when the paper transitions to the fuser, the timing is off just a bit and it lags? I believe they upgraded the drive pack on this model to add a clutch to it, but you also have to upgrade the engine board. I don't know if that would help with this issue.

I have a few ideas for my next step, but would love to see what advice is out there. Thanks in advance.
5050 Sample 2.jpg 5050 Sample LTR.jpg

**nathansipe** · 06-01-2016

Update. I replaced the fuser unit and adjusted the plastic plate on the front frame with no changes. I played with the loop adjustments and timing adjustments with no improvement.

I ran Legal paper through it and the problem still shows up 2 inches from the trail end of the print. Interesting that is not the same spot as the letter as far as distance from the lead edge but it is the same from the trail edge.

**blackcat4866** · 06-02-2016

That's why I think it's about fuser alignment. The paper gets an uneven buckle, which when released, shifts the paper to the front or rear. That measurement will be the exact dimension from the center of the registration rollers to the center of the transfer roller.

Speaking of transfer, have you looked at the transfer roller bushings and springs? It's common to have the rear bushing break, the spring falls out, then the enduser put's the roller back without the spring. =^..^=

**nathansipe** · 06-02-2016

I thought so too, however, after replacing the fuser, I changed the fuser alignment to the left 2 increments then to the right 2 increments with no affect on the print either way. After running the legal paper, I've been thinking that since it messes up 2 inches from the trail end no matter the paper size, is there a clutch that kicks on at the time the last 2 inches are at the drum? Therefore lagging the paper just a bit. There are no clutches in the drive pack and the registration clutch would already be on. Maybe exit section?

I'm bringing the machine to the shop tomorrow so I can dive into it a bit more.

**NeoMatrix** · 06-02-2016

Run a bypass A5 and then A3 to see if it's constant with the paper path.

As BC stated previous: I'm leaning toward transfer springs or broken guide dowel.

**blackcat4866** · 06-02-2016

I seem to recall having the fuser drive apart on one occasion. There is no clutch, just a motor and drive gears. I've seen those gears worn, and I've seen the ring gear split. But I disagree about a clutch problem. The paper is turning in the vertical path. When the registration roller releases the paper shifts. Measure, you'll see. =^..^=